Teensy tiny Arduino board with an ATtiny85

Planning another Arduino build? If you’re just doing something simple like switching a relay or powering a LED, you might want to think about the Digispark. It’s a very small ATtiny-based Arduino compatible board developed and Kickstarted by [Erik].

The Digispark is based on the very popular Atmel ATtiny85, an 8 pin microcontroller that provides a quarter of the Flash storage and RAM as the ‘official Arduino’ ATMega328p. The lower storage space and RAM doesn’t mean the ’85 is a slouch, though; it can run Arduino code without a hitch, providing six pins for whatever small project you have in mind.

Right now, [Erik]’s Kickstarter is offering three Digisparks for the price of a single Arduino. At that price, it’s cheap enough to leave in a project and not be repurposed after the build is over. [Erik] is also working on a few shields for the Digispark – only RGB LED shield for now, but hopefully he’ll get some more finished by the time the Kickstarter ends.

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55 thoughts on “Teensy tiny Arduino board with an ATtiny85”

This looks good in quite a few ways. Most of all, the price makes it trivial to buy a bunch of these and do whatever with them. Additionally, it’s even smaller than the TeensyUSB boards, making this perfect for tiny stuff, down to wristwatch size.

I kind of wish there was a perforation along the USB connection so it could just be snapped off to save space.

Maybe it’s pricey parts-wise, but how many other similarly priced, similarly tiny arduino boards are out there? The Teensy costs $16 and is larger, plus you need a $3 mini USB adapter. Seems to me like this guy is about to make a profit on a good idea (the PCB USB connector) that you didn’t think of.

How do you figure that it’s pricey? I’ll agree that shipping kills it (to Canada at least), but it’s not pricey considering it provides the Tiny as well as the USB interface. An ATTiny85 cost $1.50 alone. for an end-to-end arduino solution that you can directly program, it’s a great deal.

If it’s $10 for a single board with free shipping, then the price is OK (soso). But these things only have maximal 6-bit IO (more like 4). If you do any USBGPIO, 2 bits must be used by USB. Plus the ATTiny must be running V-USB to do it.

A USBRS232 adapter costs $2.75 with free shipping. It only has 2 usable output control lines, but “if you’re just doing something simple like switching a relay or powering a LED” as the description says, it’s a lot cheaper. HAD also did an article explaining the cheap ones are in fact 5v TTL rs232 (none of that legacy +/- 25v nonsense).

There are all great alternatives to the Digispark and we’ll also release all the specs once they are finalized for anyone who wants to make their own.

As for the price of the Digispark – $8 each at quantity is very (very!) near cost because of our decision to produce the PCBs and assemble in the US – we’ve found that US SMT assembly is pretty pricey.

Sure, you’ll be able to build them for around $6-$7 – if you buy enough inventory to build in quantities of $10. You’d be looking at around $100 in costs then. Plus your time to solder what will become a commodity circuit/PCB.

There’s educational value in DIY the above, especially if you’ve never soldered SMT or ordered a board before. No doubt.

Or you could consider the ~25% to be a meal tip on good service, to encourage more people to solve problems like this. It’s still open source when you tip. :-)

Seems more practical to pay the asking price and put those dollars and minutes towards the custom portion of whatever you are building.

My only suggestion is they drop the USB port to reduce costs, and just offer pin headers. This is partly intended to be a “permanent” install.. and with the potential lower price it’s also practical enough for “throwie” disposable applications.

Similar to a setup I did a couple weeks ago. Targeted for ATiny84 because I needed the extra IO, but it could be reconfigured for ATTiny85. The eagle files are available. Getting a custom board made by someone like seeed is very affordable.

What I really want to know is how the USB programming works. I assume it’s a custom bootloader. Right now I’m programming my board with an external arduino, which is kind of a pain.

I wonder what they’ll be doing for the USB vendor and product ID? I guess with all the money they’ve raised, the fee won’t be an issue.

There is still the problem of the V-USB implementation being out of USB spec, and not reliable. It can work, but depends on the computer, cable, hub, etc being used. The SOIC-8 they’re using is the same size as a VQFN-32, which means they could use an ATMega32u2 instead. That would give them a real USB peripheral, with no CPU-hungry time sensitive software USB getting in the way. That’s why the PJRC Teensy works well.

the bootloader hooks in to the pinchange interrupt and you’re right, the timing on that is different to if you run with no bootloader, but the little delay is small enough to not cause any trouble with running V-USB apps on it. All the other interrupts work in the usual fashion.

A while back I made myself a “development board” for an ATtiny45, which is the same thing as an ATtiny85, but with less program space and RAM. Since I have an AVRISP mkII programmer from Atmel, I skipped on the USB interface and just added an ISP header. My board does not have power regulation built in either, that is provided by a generic linear supply I built as a separate board or my bench’s supply as needed. Given the hard costs I incurred [materials and PCB production], I would say the cost they are asking for that board is fine, if not cheap.

In the vein of something similar, besides the Sparkfun AVR stick, figured I’d mention the SB-FireFly is about the same price tag (for a limited time). For programming, like Orlando, it has as ISP jack instead of USB conn. and takes advantage the MIT High-low tech group’s hack for Arduino 1.0 (which the Digispark may use as well for inputting the ATTiny85 core files). I’m not sure if I like the on-board regulator idea as it adds to cost and the nice thing about many Atmel chips is that they can run off voltages as low as 2.7, so a couple ‘AA’s or a 2032 coincell (included with the FireFly) could be used.

In Australia I use the freetronics Leo-stick that i got from a local supplier at squarebit.
(http://www.squarebit.com.au/product/77/)
It is a small arduino leo compatible board in a USB form factor. not as cheap but still good for what it has on board!

I can see beginners like myself buying it as It’s relatively cheap and it’s less intimidating than a full blown Arduino. Looking at the Arduino Uno at Radio Shack with all of its I/O pins left me with a feeling that I imagine medical students get before cutting open their first cadaver.

A bit sick of that arduidiot things really. Making a USB AVR ATTiny85 is nothing new /at all/. I did one over 3 years ago, single side PCB. I know some other did it too, probably even earlier. Now someone comes with the “arduino” tag and it’s “news”. Get a grip people, “arduino” is a tag made up to make you cought up twice the money for very, VERY simple hardware.

Sigh…
As a happy [arduino*,teensy, digispark,PIC,AVR] user who has done [breadboard,perfboard,ferric chloride/DIY PCBs, EuroFab,USFab,ChinaFab], and who has more project ideas than hobby time, I find the ’85 based digispark is great for embedded animation projects where I want to focus on the animation, not the electronics. Sure, I could (and have) DIY’d my own tiny* boards, but there is no way I can {order parts, fab boards, stuff boards, test boards, burn bootloaders, rework dead boards} at a 1x or 2x volume fast enough to cover my lost opportunity cost. Getting a ready-to-use board for a $5/ea premium – and avoiding the evening it would take to roll my own is, as the commercial says, priceless.

Why is everyone bitching about the price? Either it’s the right price for you or it isn’t. If it isn’t, walk away. Complaining never brings the price down for these little self-produced products. Maybe if you sent a well-written letter with proposals for volume buys to bring the prices down you could get a deal, but whining never accomplishses anything.

Well it does often . What a silly point of view.It tells them it needs to be cheaper. It will get cheaper soon enough for me as others mass produce copies.
These people want one but want a cheaper price . The vendors want that price . All comes to equiblibrium fairly quickly with price issues